12.3.8.2 Principle of operation
The users of the Circuit switch (SXSWI) is other functions such as for example, switch
controller, protection functions, autorecloser function, or a 61850 client residing in
another IED or the operator place. SXSWI executes commands, evaluates block
conditions and evaluates different time supervision conditions. Only if all conditions
indicate a switch operation to be allowed, SXSWI performs the execution command. In
case of erroneous conditions, the function indicates an appropriate "cause" value.
SXSWI has an operation counter for closing and opening commands. The counter
value can be read remotely from the operator place. The value is reset from a binary
input or remotely from the operator place by configuring a signal from the Single Point
Generic Control 8 signals (SPC8GGIO) for example.
Local/Remote switch
One binary input signal LR_SWI is included in SXSWI to indicate the local/remote
switch position from switchyard provided via the I/O board. If this signal is set to
TRUE it means that change of position is allowed only from switchyard level. If the
signal is set to FALSE it means that command from IED or higher level is permitted.
When the signal is set to TRUE all commands (for change of position) from internal
IED clients are rejected, even trip commands from protection functions are rejected.
The functionality of the local/remote switch is described in figure
342.
From I/O switchLR
TRUE
FALSE
Local= Operation at
switch yard level
Remote= Operation at
IED or higher level
en05000096.vsd
IEC05000096 V1 EN
Figure 342: Local/Remote switch
Blocking principles
SXSWI includes several blocking principles. The basic principle for all blocking
signals is that they will affect commands from all other clients for example, operators
place, protection functions, autorecloser and so on.
The blocking possibilities are:
Section 12 1MRK505222-UUS C
Control
676
Technical reference manual
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